Today's Message Index:
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1. 07:55 AM - Re: How do you figure C-Rating of a battery? (rparigoris)
2. 07:56 AM - Re: How do you figure C-Rating of a battery? (rparigoris)
3. 08:40 AM - Re: Re: How do you figure C-Rating of a battery? (Charlie England)
4. 08:58 AM - Re: Re: How do you figure C-Rating of a battery? (Robert L. Nuckolls, III)
5. 09:08 AM - Re: Re: How do you figure C-Rating of a battery? (Robert L. Nuckolls, III)
6. 10:57 AM - Re: Re: How do you figure C-Rating of a battery? (Charlie England)
7. 02:37 PM - Re: How do you figure C-Rating of a battery? (Martymason)
8. 03:38 PM - Fw: Re: Alternator/Strobe whine (user9253)
9. 04:17 PM - Re: How do you figure C-Rating of a battery? (rparigoris)
10. 06:24 PM - Re: Fw: Re: Re: Alternator/Strobe whine (Robert L. Nuckolls, III)
11. 07:41 PM - Re: How do you figure C-Rating of a battery? (user9253)
12. 08:09 PM - Re: Re: How do you figure C-Rating of a battery? (Robert L. Nuckolls, III)
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| Subject: | Re: How do you figure C-Rating of a battery? |
Hi Group Thank you for replies. Again I want a dual mission total loss battery, one to run a Rotax 914 fuel pump which I'm certain the 5,000mA cells are up to the task and two is to jump start main battery in a pinch. My dilemma is if I hook up NiMh pack to a flattened Earth-X battery the amp draw can be quite high. Not sure just how high and not sure how many amps the NiMh cells can dump. OK let's take a different tact for in a pinch jump starting. I posted a link to discharge table up to 20 amps for NiMh cells. I feel confident those cells can handle a discharge rate of 30 amps. What's thoughts of using this to limit amperage draw on NiMh cells when using them to jump?: http://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=184069714833&category=117000&pm=1&ds=0&t=1596298535000&ver=0
I have EZ pilot access on passenger headrest where I could make a series converter
with red and black Anderson Power Pole connectors. Ron P.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498332#498332
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| Subject: | Re: How do you figure C-Rating of a battery? |
Hi Group Thank you for replies. Again I want a dual mission total loss battery, one to run a Rotax 914 fuel pump which I'm certain the 5,000mA cells are up to the task and two is to jump start main battery in a pinch. My dilemma is if I hook up NiMh pack to a flattened Earth-X battery the amp draw can be quite high. Not sure just how high and not sure how many amps the NiMh cells can dump. OK let's take a different tact for in a pinch jump starting. I posted a link to discharge table up to 20 amps for NiMh cells. I feel confident those cells can handle a discharge rate of 30 amps. What's thoughts of using this to limit amperage draw on NiMh cells when using them to jump?: http://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=184069714833&category=117000&pm=1&ds=0&t=1596298535000&ver=0
I have EZ pilot access on passenger headrest where I could make a series converter
with red and black Anderson Power Pole connectors. Ron P.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498333#498333
Message 3
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| Subject: | Re: How do you figure C-Rating of a battery? |
On 9/13/2020 9:53 AM, rparigoris wrote:
>
> Hi Group Thank you for replies. Again I want a dual mission total loss battery, one to run a Rotax 914 fuel pump which I'm certain the 5,000mA cells are up to the task and two is to jump start main battery in a pinch. My dilemma is if I hook up NiMh pack to a flattened Earth-X battery the amp draw can be quite high. Not sure just how high and not sure how many amps the NiMh cells can dump. OK let's take a different tact for in a pinch jump starting. I posted a link to discharge table up to 20 amps for NiMh cells. I feel confident those cells can handle a discharge rate of 30 amps. What's thoughts of using this to limit amperage draw on NiMh cells when using them to jump?: http://vi.raptor.ebaydesc.com/ws/eBayISAPI.dll?ViewItemDescV4&item=184069714833&category=117000&pm=1&ds=0&t=1596298535000&ver=0
> I have EZ pilot access on passenger headrest where I could make a series converter
with red and black Anderson Power Pole connectors. Ron P.
>
>
I think we still don't have enough detail on your hypothetical
'situation' needs. On the one hand, you're talking about powering just a
fuel pump (implying a total electrical failure), and the other about
either jump-starting the engine, or recharging a dead battery, but we
don't know if that means a failed charging system or just a run-down
battery.
We do know that NiMh cells have much lower energy density than any of
the lithium tech. Transferring energy to a lithium tech battery from
NiMh cells just doesn't sound like a reasonable path to me, for a
variety of reasons.
I'm pretty 'cheap'; I've been known to expend prodigious effort to save
a few $. But from what I think I understand about your goals, I'd find
it hard to resist just picking up one of the dozens of lithium 'jump
start' packs. They have high current cables for jump starting, and
almost all of them now include smaller terminals, adapters, etc that
allow connection of devices with lower current demands. $55-$75 will get
you pre-packaged cells, cables, a handful of adapters, etc, very close
to 'plug&play'. I'll bet that by the time you gather up all the stuff
you need to make your idea work, you'll have close to that much money
tied up, and a *lot* more work. Way more starting current than you'd
ever need, and even the cheapest versions will have more total energy to
run the fuel pump than the NiMh cells.
Charlie
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| Subject: | Re: How do you figure C-Rating of a battery? |
At 09:53 AM 9/13/2020, you wrote:
>
>Hi Group Thank you for replies. Again I want a dual mission total
>loss battery, one to run a Rotax 914 fuel pump which I'm certain the
>5,000mA cells are up to the task and two is to jump start main
>battery in a pinch.
Is there a history for the failure modes
you are hypothesizing? Under what series
of events would you find it necessary to
operated a fuel pump from it's own back
up battery?
Jump start? Lithium main battery? Going
airborne with an essentially dead main
battery after jump starting the engine
is poor practice. Not recommended in
any advice I've read or written.
How hard is it to (1) prevent the main
battery from becoming depleted while
parked and (2) maintaining the main
battery in a manner that guarantees
availability for alternator-out
situations?
I think we're all having trouble
understanding justification for what
you propose.
Bob . . .
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| Subject: | Re: How do you figure C-Rating of a battery? |
>I'm pretty 'cheap'; I've been known to expend prodigious effort to
>save a few $. But from what I think I understand about your goals,
>I'd find it hard to resist just picking up one of the dozens of
>lithium 'jump start' packs. They have high current cables for jump
>starting, and almost all of them now include smaller terminals,
>adapters, etc that allow connection of devices with lower current
>demands. $55-$75 will get you pre-packaged cells, cables, a handful
>of adapters, etc, very close to 'plug&play'. I'll bet that by the
>time you gather up all the stuff you need to make your idea work,
>you'll have close to that much money tied up, and a *lot* more work.
>Way more starting current than you'd ever need, and even the
>cheapest versions will have more total energy to run the fuel pump
>than the NiMh cells.
>
>Charlie
Sure. If he drops the 'jump start' requirement
but has an FMEA driven justification for a
stand-by battery on the fuel pump, these batteries
connected in series would run the pump for a very
long time . . . probably duration of fuel aboard.
https://tinyurl.com/y4oulfy9
Down side is the legacy stand-by-battery-cost-
of-ownership for insuring continued air worthiness.
I'd like to understand what conditions would drive
the need in the first place.
Bob . . .
Message 6
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| Subject: | Re: How do you figure C-Rating of a battery? |
On 9/13/2020 11:06 AM, Robert L. Nuckolls, III wrote:
>> I'm pretty 'cheap'; I've been known to expend prodigious effort to
>> save a few $. But from what I think I understand about your goals,
>> I'd find it hard to resist just picking up one of the dozens of
>> lithium 'jump start' packs. They have high current cables for jump
>> starting, and almost all of them now include smaller terminals,
>> adapters, etc that allow connection of devices with lower current
>> demands. $55-$75 will get you pre-packaged cells, cables, a handful
>> of adapters, etc, very close to 'plug&play'. I'll bet that by the
>> time you gather up all the stuff you need to make your idea work,
>> you'll have close to that much money tied up, and a *lot* more work.
>> Way more starting current than you'd ever need, and even the cheapest
>> versions will have more total energy to run the fuel pump than the
>> NiMh cells.
>>
>> Charlie
>
>
> Sure. If he drops the 'jump start' requirement
> but has an FMEA driven justification for a
> stand-by battery on the fuel pump, these batteries
> connected in series would run the pump for a very
> long time . . . probably duration of fuel aboard.
>
> https://tinyurl.com/y4oulfy9
>
> <https://tinyurl.com/y4oulfy9> Down side is the legacy
> stand-by-battery-cost-
> of-ownership for insuring continued air worthiness.
> I'd like to understand what conditions would drive
> the need in the first place.
>
>
> Bob . . .
>
As I said in the earlier section of that post, we don't know his actual
needs. But if 'jump start' or 'recharge' involves being stuck out in the
boonies with no access to service or a charger (which could easily
happen at a paved, government-run airport in some parts of the country),
then I can see having a 'jump start' pack in my emergency kit.
There may be no reason to have a dead battery, but unfortunately, *we*
have to be figured into the equation. I managed to kill a fairly
expensive 'certified' SLA battery by leaving the 'mag switch'
controlling the electronic ignition turned on for about a week. No
excuses; my stupidity, but that didn't keep the battery from being dead.
Fortunately the plane was in my hangar at home.
Charlie
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| Subject: | Re: How do you figure C-Rating of a battery? |
[quote="nuckolls.bob(at)aeroelect"]At 09:53 AM 9/13/2020, you wrote:
Is there a history for the failure modes
you are hypothesizing?
The Europa with long wings is a motorglider. Hence the need to restart in air.
I think Ron is looking for belt & suspenders.
Marty Mason
--------
Marty Mason
Norcross, GA
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498340#498340
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| Subject: | Re: Fwd: Re: Alternator/Strobe whine |
Check the AC component of the alternator output.
It should be less than 1 volt AC. More than that means a diode is bad.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498341#498341
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| Subject: | Re: How do you figure C-Rating of a battery? |
Hi Bob Here's a few pics of under 2 lb battery: http://www.europaowners.org/main.php?g2_itemId=27335 and http://www.europaowners.org/main.php?g2_itemId=30614 the batteries are getting old and I want to replace them with 10 year newer NiMh technology. You sent a link for a LiPo battery, true they have great energy density but LiPo is also one active Lithium technology, no place in an aeroplane IMHO. My reasons for wanting a independent battery for a fuel pump is in case main battery stops working for whatever reason. Side note, Europa has a main tank and a reserve just like a motorcycle. Run out of fuel and turn to reserve and you know how long it will last. My reason for total loss battery to run a pump is pretty much the same. If you can no longer supply power to a pump, I'll call on my "reserve battery". Potential things that would cause a failure of E-Bus is a battery that fails opened. Yes yes yes I have read read read read that if you capacity test a battery once a year and replace often that the chance of a failure to occur after the motor is started is very slim. I have had at least 2 failures on a car when driving and battery opened and engine quit. Once on a motorcycle where things went dark but engine still ran. Now I'm introducing a LiFe Earth-X battery that is not a lead acid and as far as I'm concerned unquestionably has the potential to offer up no potential for other reasons besides internal connections going very high resistance. I have a SD20S with LR3C on vacuum pad of Rotax 914, I haven't any experience with SD20S and LR3C, but I did have a Suzuki Samari with a ND alternator, it had a solid state internal regulator, anyway the regulator failed, cooked the battery and I got stuck on the side of the road. True LR3C has over-voltage protection but could it fail and cook my battery? I'm using Eric Jones aluminium clad wire (battery in back), I crimped and soldered and paid a lot of attension to smooth bends and support, but there are several connections that could fail and go high resista!
nce and
make my E-bus inoperative. If I take a long and extended flight with additonal
fuel onboard, if charging system failed and I was flying off of E-Bus, then engine
quit because battery went flat either for flying too long or let's say the
fool Rotax TCU decided to draw a lot more power than it normally does and engine
quits. I just connect total loss "reserve battery". I haven't tested it yet
but if I were on total loss battery, I think I could cycle it on and off and
probably double range. Anyway that's my reasons for being able to run a fuel
pump. Just recently I figured since I have this battery already, I could use
it as a in a pinch jump start pack. This would be just a value added. I agree
with you taking off with a battery that's flat is a bad idea. Let's say I'm in
the middle of nowhere and camping out. Some load was left on and battery is a
bit flat. If I could let the total loss battery charge the main battery for a
bit then try a start, if it started I would be gentle and use only the SD20S
to charge on ground for a while at reasonable rate before taking off. If I have
a choice I don't fast charge. Another scenario is after shutting down motor
and soaring for a while, for some reason the engine will not start. If you shut
down motor you always want a landing spot at hand assuming that the motor won't
start. Let's say for whatever reason the battery can't offer up enough electron
flow to do an inflight restart, could be too much a load was left on, bad
cell in battery or plain bad luck, true if had enough altitude could go course
pitch and do an airstart, kinda hard on a cold engine and you need a reasonable
amount of altitude, anyway if I was able to do an inflight jump start, just
an added bonus. The under 2 pounds lets me sleep a little better knowing I
could keep the motor running if all else fails. Unquestionably belt and suspenders,
hope I never need to use it. Ron P.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498342#498342
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| Subject: | Re: Alternator/Strobe whine |
At 11:03 PM 9/12/2020, you wrote:
>So it is alternator whine. It's present when the strobes are off.
>When they're on, it does warble a bit. There is a bit of strobe
>noise with both alternators off and just the battery on but it's not
>obnoxious at all. There's no noise at when running on the backup alternator.
>
>--Rick
This about has to be a grounding issue.
Refresh my memory. What kind of airplane?
Can you describe your ground system? Conforms
to recommendations in Z15/Chaper 5 in the
'Connection?
Bob . . .
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| Subject: | Re: How do you figure C-Rating of a battery? |
Can a dead battery be recharged by a fully charged battery?
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=498346#498346
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| Subject: | Re: How do you figure C-Rating of a battery? |
You've stacked a bucket load of suppositions
and hypotheticals for which I perceive no
foundation. Most of the things you're worrying
about are the same things we've been working
to mitigate for the last 100 years or so.
Worried about crimped AND soldered connections?
Why? No, LR3s have no failure modes that would
cook a battery.
LiFEPO4 has an excellent design history and
track record when packaged with a BMS. AeroVolz,
EarthX, TruBlue and others have done their
homework.
AeroVolts has a BMS fitted battery right
at 2 pounds and proofs out at 4.5AH . . .
it will even crank an engine.
What kind of charge/maintenance protocol
are you proposing for your home brew array?
> Unquestionably belt and suspenders, hope I never need to use it. Ron P.
Ron, of all the electrically involved
accidents I've worked, the vast majority
had root cause in inattention to mechanical
or architectural design details. I.e. poor
FMEA and/or craftsmanship. When component
failure was part of the script, it was almost
never due to manufacturing defect . . . in
fact I cannot now recall a single instance.
Consider sharing your architecture drawing
with the List . . . let's run it under the
FMEA microscope before you pile on Band-Aids
more likely to produce complexity induced
risk. Better to prevent the injury than to
carry tourniquets and field dressings.
Bob . . .
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